<!DOCTYPE html>
<html lang="en">

<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>demo</title>
</head>


<body>


</body>
<script type="text/javascript">
let {length : len} = 'hello';
console.log(len); // 5
</script>

</html>